Individuals who are functionally blind due to eye injuries or diseases of the cornea often use rigid gas permeable (“RPG”) contact lenses. In particular, such individuals often utilize a Scleral TM lens, which is frequently referred to as a “bandaged” lens.
When inserting an RGP lens, or a Scleral TM lens which contains a large volume of fluid, it is critical that the user keep the lens aligned with the user's eye. The alignment involves both centering the lens on the eye and aligning the lens on a perpendicular axis to the eye. The lens must be centered and square to the eye for a successful insertion.
If a Scleral TM lens is misaligned during insertion, the fluid may spill out. Moreover, a slight misalignment of an RPG or Scleral TM lens may cause the lens to hit the user's eyelid or finger and fall out. Additionally, insertion of a lens such that it is only partly on the cornea or in the corner of the eye can cause injury. Flinching, blinking or premature closing of the eye at insertion can also cause insertion failures. Even if an imperfect alignment does not cause injury but aligns by flipping onto the sclera, there is a good chance that bubbles will be formed in the fluid reducing the efficacy of the lens.
Typically, when inserting such lenses, a user will employ a mirror or other means to align the lens with an eye. Users with low vision, however, have great difficulty using a mirror or other method in which they must visualize the lens to align it for insertion. Moreover, even with regular contact lenses, i.e., non-RPG or Scleral TM lenses, alignment is difficult or impossible to achieve when the lens is very close to the user's eye. Additionally, lens wearers tend to look away from the lens at the moment of insertion. When a wearer looks away from the lens, the lens is often inserted in a misaligned state.
The present invention addresses the above-identified problems. The present invention utilizes a generated light source that is focused and projected upward from the bottom surface of a hollow plunger to facilitate alignment. The light is projected upward through the inner cavity of the plunger and through an opening in the lens holder attached to the plunger. If a user looking into the hollow plunger can see the light coming up from the bottom of the plunger through the opening in the lens holder, then the device and lens are both centered, perpendicular to the eye and ready for insertion. Furthermore, the user must focus on the light and the lens during the insertion process, reducing the probability of the user looking away from the lens at the moment of insertion.
Moreover, the present invention also assists an individual, such as a trainer or physician, in inserting a lens into a patient's eye. When an inserter uses the tool to install a lens, the light coming out of the plunger can be seen on the patient's eye. If the patient can see the light coming from the bottom of the plunger at the same time the inserter can see the light on the center of the eye, then the light beam has sighted the center of the eye and the lens is square to the eye. For the trainer who is observing the patient insert a lens, especially during the first solo attempts, he or she can observe whether the insertion process is on track by looking at the beam shining on the eye. The feedback allows the trainer to evaluate the patient's insertion technique and make any required adjustments in the technique prior to an improper insertion. This combined with the automatic feedback of the user substantially decreases training time. The feedback causes the user to constantly adjust the device and the head to remain focused on the light at the end of the plunger.
The present invention utilizes a targeting or “gun barrel” effect to achieve alignment. The placement of a light source at the bottom of the inner cavity of the plunger and the configuration of the lens holder creates this effect. If a user sees the light at all, or sees light in the center of the field of light, depending on how the device is made the lens is perfectly aligned and ready to insert. The device holds the lens firm through suction.
Additionally, the present invention overcomes significant drawbacks of the prior art that have attempted to address the above-identified problems. Prior art insertion devices generally employ a light located on the top surface of the insertion tool close to the eye of the contact wearer, which creates no targeting effect and does not assist in alignment as does the present invention.
Other prior art devices, such as the handling tool disclosed in U.S. Pat. No. 4,026,591, hereby incorporated by reference in its entirety, employ a natural light source, i.e. the ambient light in a room, to guide alignment. This light is insufficient for those with low vision and is likely insufficient for all contact wearers in low light or changing light environments. To compensate for this significant shortcoming, the prior art handling tool includes a large, complex eye cup and steady rest which contact the face of the user to ensure alignment. The present invention overcomes this drawback by proposing an insertion tool that provides a beam of generated light travelling along an inner longitudinal axis of the tool that is clearly visible to individuals with low vision.